When New Jersey Governor Chris Christie quietly opted for weight-loss surgery in February, he chose the safest — but often least effective — procedure.

Patients who undergo gastric-band surgery — Lap-Band is the trade name — can lose between a third to half of their body weight. But about 10% of patients lose nothing at all, says Dr. Philip Schauer, a bariatric surgeon at the Cleveland Clinic who was not involved in Christie’s care.

Before surgery, Christie weighed about 350 lb., estimates Schauer. “He’s about 150 pounds overweight so a very good result would be if he lost 75 pounds,” says Schauer. “But he would still be overweight at 275 pounds.”

Gastric-band surgery is usually performed laparoscopically, with surgeons cinching an adjustable silicone band around the patient’s stomach, limiting the amount of space for food. Adding saline to the band makes it tighter; in the first year after surgery, patients typically visit their physician six or so times to have the band adjusted. The snugger the band, the less hungry people feel. “They eat less because they feel full quicker,” says Schauer.

Two other commonly performed weight-loss procedures typically yield more dramatic results, but they’re also more invasive.

Gastric bypass involves stapling the upper stomach to fashion a small stomach pouch, decreasing its size from that of a football to a golf ball. A portion of the intestines is bypassed so fewer calories are absorbed. Another procedure, sleeve gastrectomy, makes the stomach smaller by removing the outer part and reducing the stomach pouch to the size of a banana.

For Christie — a public figure who didn’t have the luxury of down time — gastric band surgery was the most sensible choice. “He had to go back to work very fast. He was not going to take three or four days out of work for a bigger surgery,” says Dr. Alfonso Torquati, director of the Duke Center for Metabolic and Weight Loss Surgery. Torquati, an associate professor of surgery at the Duke University School of Medicine, wasn’t involved in Christie’s surgery, but he was tickled to find his line of work garnering some national buzz on Tuesday. “Gastric band is usually a day surgery — they go in in the morning and a few hours they later they can be back answering e-mails and taking phone calls.”

Whether the surgery is working is a closely guarded secret, much like the fact that Christie had the operation in the first place. His office confirms that he checked into the hospital on Feb. 16, but there’s no official word on how much weight — if any — he’s lost so far. It does appear that food doesn’t hold the allure for Christie that it once did; he told the New York Post that his appetite isn’t what it used to be. “A week or two ago, I went to a steakhouse and ordered a steak and ate about a third of it and I was full,” he said.